Mechanized harvesting operations promote a series of benefits to sugarcane production but are also a cultivation step responsible for developing a series of problems for the soil and the plants due ...to plant mechanical damage, resulting in a decline in production over successive cycles due to row gaps emergence. The objective of this study was to evaluate the impact of burned and unburned harvesting systems on the occurrence of sugarcane row gaps over annual harvests. For this study, a burned and an unburned area were selected. The row gap number and length (sum of gaps, m) were measured after the sugarcane planting and plant-cane cultivation stages and after the first, second, and third sugarcane ratoon harvests. The results revealed that there was no difference in the number and length of row gaps between the burned and unburned harvesting systems. However, the row gap number and length considerably increased after the second harvest in both treatments (burned and unburned). The row gap number and length were close to 5 and 1–5 m at the planting and plant-cane cultivation stages and increased to around 60 and 70 m as the harvest progressed, respectively, in burned and unburned harvesting. Our results suggest that row gaps in sugarcane fields are independent of the burned or unburned sugarcane harvesting system but increase as the number of harvests increases.
A field experiment was carried out to evaluate changes in soil physical properties over three successive years of sugarcane cultivation under burned (BH) and unburned (UH) cultivation systems. Soil ...samplings were collected after sugarcane planting, after the plant-cane harvest (H1) and after the first ratoon harvest (H2) in areas subjected to BH and UH. The degree of compactness (DC), macroporosity (MaP), soil penetration resistance (SPR), total organic carbon, field water content (
θ
) and water content at field capacity (
θ
FC
) were measured. Moreover, the amount of surface straw was measured after H1 and H2. Soil physical quality was considerably reduced after H1 regardless of the harvest systems. Annual successive harvests increased DC by 10%, reducing MaP by about 50% and increasing SPR. The negative effects of the successive harvests were slightly greater at BH because of the lowest amount of sugarcane straw on the soil surface, which considerably reduced
θ
. It can be concluded that successive harvests reduce the soil physical quality in burned and unburned harvest systems after the first harvest, but the negative effect is more prominent in areas with straw burning.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Tillage intensity and successive harvesting before sugarcane replanting are practices that may result in the formation of compacted layers. Compaction alters soil structure and influence soil water ...retention, soil aeration and soil strength. Thus, this study was designed to assess the soil physical indicators associated with water, air and soil strength functions of a sugarcane field subjected to six successive mechanised harvests. The experiment was performed in 2018 in sugarcane fields from the Carpina sugarcane experimental station, Pernambuco, Brazil. In situ penetrometer measurements were made, and soil cores were sampled at depths of 0–0.20, 0.20–0.40, 0.40–0.60, 0.60–0.80 and 0.80–1.00 m for determination of soil penetration resistance, field capacity and soil bulk density. We calculated the degree of compaction, water capacity and air capacity of cultivated soil and compared the results with indicators of a native forest soil adjacent to the experimental area. The results showed that successive sugarcane cultivation declined the soil physical quality for plant development. Measurements showed that the deterioration of soil physical quality occurs mainly up to 0.40 m depth, which is a layer that undergoes tillage intervention and is susceptible to the formation of plough pan below the tillage depth. An increase in soil compaction, strength and loss of aeration capacity were the main sources of the decline in the soil physical quality. These soil physical factors are known to cause severe restrictions to root development and plant performance. The alleviation of soil compaction with subsequent monitoring of the impact of field traffic (e.g. through machinery and soil conduction controls) could help prevent the decline of soil physical quality in sugarcane areas.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
•Sugarcane cultivation reduced soil porosity, C and aggregate stability.•Soil structural benefits are declined during tillage for sugarcane replanting.•Soil tillage for sugarcane replanting ...alleviates soil hardening.•Sugarcane cultivation declines performance of soil physical functions.
In northeastern Brazil, the sugarcane expansion has occurred historically over the Atlantic Forest biome. However, little is known about the physical process and changes induced by sugarcane cultivation in this biome. Thus, a field study was conducted to evaluate changes induced by sugarcane cultivation on soil physical properties, processes and functions in the Atlantic Forest biome. For that, soil samples were collected at three sites in northeastern Brazil: AF – Atlantic Forest, SCratoon – successive sugarcane ratoon cultivation and SCtill – tilled soil for sugarcane replanting. Quantitative and semi-quantitative soil properties i.e. bulk density, soil penetration resistance (SPR), water-stable aggregates, soil organic carbon (C), pore size distribution and Visual Evaluation of Soil Structure (VESS) scores were examined. In addition, four critical soil functions were evaluated by a soil physical quality index (SPQI). Atlantic Forest soil presented the greatest soil physical quality (i.e. lower bulk density, higher porosity, soil C and soil aggregate stability), functioning, according to SPQI, at 88% of its full capacity. However, SPR under AF was significantly higher than SCratoon and SCtill. Soil tillage reduced SPR in SCtill compared to the area under successive sugarcane cultivation (SCratoon). The results revealed that the high SPR in AF and SCratoon areas occurred without soil volume variation (i.e. no compaction) in relation to the SCtill, indicating that these soils are susceptible to hardening induced by C bonds and thixotropy processes. Soil tillage for sugarcane replanting resulted in immediate improvements on physical conditions for root growth by decreasing SPR; however, soil disturbance increases its susceptibility to degradation by reducing water-stable soil aggregate, organic C and aeration pores. Thus, sugarcane cultivation declined the performance of soil physical functions to 72 and 67% of its full capacity in SCtill and SCratoon, respectively. Finally, best management practices to reduce soil disturbance and increase C should be prioritised, as well as minimising the mechanisms responsible by soil hardening in order to reduce soil physical degradation and improve the environment for root growth in sugarcane fields.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Soil physical proprieties were investigated in response to sugarcane harvest.•Compaction is more prominent at the topsoil.•Organic carbon increase at the topsoil along the successive ...harvests.•Organic carbon helps to alleviate the compaction.•Only small changes occur at the subsoil due to existence of a residual plough pan.
Soil degradation due to agricultural field traffic is a serious issue affecting soil functions in modern agriculture. With sugarcane cultivation, the number of harvests through successive ratoons has become a challenge for the maintenance of soil quality in the topsoil and subsoil. The objective of this study was to evaluate physical and mechanical responses of soil to successive harvests under sugarcane cultivation in an Ultisol of coastal tablelands in Northeastern Brazil. Disturbed and undisturbed soil samples were collected from five sites at depths of 0–0.20 m (topsoil) and 0.20–0.40 m (subsoil), in which one, two, three or four harvests had taken place. In addition, one site had been kept without cultivation for one year after a sugarcane crop. Organic carbon (OC), maximum soil bulk density (BDmax), critical water content (wc), degree of compaction (DC), precompression stress (σp), compression index (CI) and the angle of internal friction (φ) were measured and subjected to multivariate analyses for the different sugarcane ratoons. Soil compaction indicators and OC in the topsoil were sensitive to the number of harvests, where compaction and OC increased with each ratoon sugarcane crop. The increase in OC with successive harvests resulted in a decrease in the BDmax and an increase in the wc, which suggest that optimum water content for compaction is moved to wetter zone due organic matter effects. The DC increased considerably after the third harvest, and it was at a maximum level before the sugarcane renovation (i.e. at the harvest immediately before the new seeding). In the subsoil, immediately below the plough layers, where plough pan formation typically occurs in conventional tillage, considerable changes in the soil physical and mechanical indicators are unlikely to occur due to the persistence of compacted layers. The increase in the organic carbon content results in better soil physical condition in the soil surface, but the degree of compaction may slightly increase due to frequency of traffic caused by the increase in the number of harvests, becoming compaction more severe close to the sugarcane renovation.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Compressive parameters were examined at around field capacity.•Soil compressibility is almost entirely governed by the silt + clay content.•Strength and swelling components were not influenced by ...soil texture.•Soil organic carbon decreased strength and increased soil swelling.
Large-scale sugarcane plantation is characterized by successive and disordered traffic of heavy machinery and equipment over the cycle, which can cause damage to the soil structure. As the stress induced by traffic exceeds the soil load-bearing capacity, it results in soil compaction. However, the mechanisms and key variables that govern the compressive characteristics in agricultural unsaturated soils to support those applied loads without plastic deformations (compaction) is not fully understood. To investigate this process, we measured the strength, swelling and compressibility characteristics of unsaturated soils with contrasting texture from sugarcane fields. Undisturbed soil cores were sampled in nine cultivated sugarcane fields, equilibrated at a matric potential of –100 hPa and subjected to confined uniaxial compression tests. Precompression stress (σp), compression (λ) and swelling (κ) indexes were extracted from the soil compression curves. Soil organic C (SOC), degree of compactness, total porosity and particle size fractions were also measured and correlated to the compressive parameters σp, λ and κ. Principal components, correlation and multiple regression models were used to the data analyses. Overall, reductions in soil strength and increases in the soil compressibility and elasticity occurred with the increase in SOC, whereas increases in the degree of compactness resulted in higher soil strength and lower soil compressibility and elasticity. Furthermore, our results revealed that silt + clay content considerably increased soil compressibility. In combined scenarios for a range of soil texture, SOC and degree of compactness at matric potential at around field capacity (i.e. –100 hPa), the maximum σp observed was approximately 200 kPa, which is a much lower load-bearing capacity than the estimated stress for some trucks and trailers used in sugarcane harvest (∼600−800 kPa). Our study suggests that soil compaction is eminent in sugarcane fields at matric potential close to field capacity, and can be aggravated in clayey soils with high SOC content and low degree of compactness. Therefore, urgent strategies of traffic control are necessary to prevent or mitigate soil compaction induced by mechanized sugarcane operations.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Maize crop under rainfed conditions is widely grown in the Brazilian Northeast on community farms for human and animal consumption. The application of mulch could be adopted to enhance rainwater ...harvesting and soil moisture levels, although such practice is rarely applied in rainfed cultivation. This study aimed to evaluate the spatial variability of maize productivity, based on soil physical attributes and plant growth and yield, under a rainfed regime in the presence and absence of mulch in the Brazilian semi-arid region. The study was conducted from May to September 2016 in Pesqueira--PE (locality of the Semiarid of Pernambuco State, Northeast, Brazil), during which the development and production of maize in experimental plots were evaluated, and maize was grown using the traditional cropping system with and without mulching. Two grids with 40 points in a 4 x 10 m mesh were established, with spacing of 1 m for soil sampling and maize biometric evaluation. For statistical analysis, 30 samples were randomly selected from each plot. Maize cultivated in the presence of mulch showed higher development, with symmetrical distribution for all variables except for soil moisture and stem diameter. Sand content, soil moisture, height of the first cob, number of leaves, leaf length, plant height, and cob weight presented moderate to strong spatial scale dependence for the two cropping conditions, with higher spatial dependence consistently observed for the development parameters in the covered area. Key words: rainfed agriculture, kriging, coconut powder, mulching, cultivar Sao Jose O cultivo de milho em sequeiro e amplamente explorado no Nordeste Brasileiro pela agricultura familiar, para alimentacao humana e animal. Para melhorar a captacao da agua da chuva e a umidade do solo, pode-se adotar a cobertura morta, embora essa pratica ainda seja raramente aplicada no cultivo de milho de sequeiro. Neste contexto, o objetivo deste estudo foi avaliar a variabilidade espacial da produtividade do milho, com base nos atributos fisicos do solo e no crescimento e producao da planta, sob regime de sequeiro na presenca e na ausencia de cobertura morta na regiao semiarida. O estudo foi realizado de maio a setembro de 2016 em Pesqueira-PE, avaliando o desenvolvimento e a producao de milho em parcelas experimentais, adotando-se o sistema tradicional sem cobertura morta e com cobertura. Estabeleceu-se dois grids com 40 pontos em malha de 4 x 10 m, com espacamento de 1 m para amostragem de solo e avaliacao biometrica. Para analise estatistica, foram sorteadas trinta amostras aleatoriamente em cada parcela. O milho cultivado na presenca de cobertura apresentou maior desenvolvimento, com distribuicao simetrica para todas as variaveis, exceto para a umidade do solo e o diametro do colmo. O teor de areia, a umidade do solo, a altura da primeira bifurcacao, o numero de folhas, o comprimento da folha, a altura da planta e o peso da espiga apresentaram de moderada a forte dependencia espacial para as duas condicoes, com maior dependencia espacial sempre observada para os parametros de desenvolvimento na area com cobertura morta. Palavras-chave: agricultura de sequeiro, krigagem, po de coco, cobertura morta, cultivar Sao Jose
ABSTRACT Maize crop under rainfed conditions is widely grown in the Brazilian Northeast on community farms for human and animal consumption. The application of mulch could be adopted to enhance ...rainwater harvesting and soil moisture levels, although such practice is rarely applied in rainfed cultivation. This study aimed to evaluate the spatial variability of maize productivity, based on soil physical attributes and plant growth and yield, under a rainfed regime in the presence and absence of mulch in the Brazilian semi-arid region. The study was conducted from May to September 2016 in Pesqueira - PE (locality of the Semiarid of Pernambuco State, Northeast, Brazil), during which the development and production of maize in experimental plots were evaluated, and maize was grown using the traditional cropping system with and without mulching. Two grids with 40 points in a 4 × 10 m mesh were established, with spacing of 1 m for soil sampling and maize biometric evaluation. For statistical analysis, 30 samples were randomly selected from each plot. Maize cultivated in the presence of mulch showed higher development, with symmetrical distribution for all variables except for soil moisture and stem diameter. Sand content, soil moisture, height of the first cob, number of leaves, leaf length, plant height, and cob weight presented moderate to strong spatial scale dependence for the two cropping conditions, with higher spatial dependence consistently observed for the development parameters in the covered area.
RESUMO O cultivo de milho em sequeiro é amplamente explorado no Nordeste Brasileiro pela agricultura familiar, para alimentação humana e animal. Para melhorar a captação da água da chuva e a umidade do solo, pode-se adotar a cobertura morta, embora essa prática ainda seja raramente aplicada no cultivo de milho de sequeiro. Neste contexto, o objetivo deste estudo foi avaliar a variabilidade espacial da produtividade do milho, com base nos atributos físicos do solo e no crescimento e produção da planta, sob regime de sequeiro na presença e na ausência de cobertura morta na região semiárida. O estudo foi realizado de maio a setembro de 2016 em Pesqueira-PE, avaliando o desenvolvimento e a produção de milho em parcelas experimentais, adotando-se o sistema tradicional sem cobertura morta e com cobertura. Estabeleceu-se dois grids com 40 pontos em malha de 4 x 10 m, com espaçamento de 1 m para amostragem de solo e avaliação biométrica. Para análise estatística, foram sorteadas trinta amostras aleatoriamente em cada parcela. O milho cultivado na presença de cobertura apresentou maior desenvolvimento, com distribuição simétrica para todas as variáveis, exceto para a umidade do solo e o diâmetro do colmo. O teor de areia, a umidade do solo, a altura da primeira bifurcação, o número de folhas, o comprimento da folha, a altura da planta e o peso da espiga apresentaram de moderada a forte dependência espacial para as duas condições, com maior dependência espacial sempre observada para os parâmetros de desenvolvimento na área com cobertura morta.
PDF
